Co-axial fitting for use with a refrigeration circuit heat reclaim apparatus

ABSTRACT

Apparatus and method for exchanging heat energy between a refrigeration circuit and a hot water system. Water is heated in a combination refrigerant desuperheater-water preheater and then conducted to hot water storage. A co-axial fitting is disclosed for mixing heated water from the refrigerant desuperheater-water preheater with water in a hot water tank prior to discharging that water to a hot water system.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a device for transferring heat energyfrom a refrigeration circuit to a hot water system. More particularly,the present invention concerns a combination refrigerant desuperheaterhot water heater, and apparatus and a method of supplying heated waterto a hot water tank.

2. Description of the Prior Art

In the typical vapor compression refrigeration system various componentssuch as a compressor, condenser, evaporator and expansion device arearranged to transfer heat energy between the fluid in heat exchangerelation with the evaporator and fluid in heat exchange relation withthe condenser. It is also known in conjunction with such refrigerationsystems to utilize a desuperheater for removing superheat energy fromgaseous refrigerant prior to circulating said refrigerant to thecondenser.

In a conventional building installation a hot water heater is providedto supply heated water to an enclosure. Many hot water heaters have acold water inlet connected to an inlet extension pipe and a hot wateroutlet extending through the top of the hot water tank. Often an inletextension pipe is connected to the cold water inlet such that theincoming water is directed to the bottom portion of the tank. In hotwater tanks water is heated at the bottom of the tank and rises suchthat a stratified tank with relatively warm water at the top and coolwater at the bottom is provided. When demand is made for hot water,water is discharged from the top of the tank at its warmest temperatureand cold water is supplied through the inlet to the bottom portion ofthe tank.

It is known to combine a refrigeration system and hot water heatingsystem such that the superheat of the refrigerant may be rejected towater to be heated such that this heat energy may be utilized to providehot water.

In air conditioning systems when cooling is required heat energy istransferred from the enclosure and discharged to the ambient or someother heat sink. This heat is often wasted. With the combination systemas disclosed herein it can be seen that this heat energy that isunwanted in the enclosure may be utilized to supply heat energy to waterto provide heated water for various end uses. This heated water may beused for bathing, cleaning, cooking or other uses in a residence.Commercial applications include restaurants, supermarkets, processutilization and any other application wherein waste energy or excessenergy from a refrigeration system may be utilized to provide some orall of the hot water heating needs. In addition to refrigeration systemsproviding excess heat for heating water during the cooling season,certain refrigeration circuits are capable of reversing the cycle ofoperation for providing heat energy to the enclosure during the heatingseason. If it is desirable some of the heat provided during the heatingseason may also be utilized to supply hot water through the disclosedhot water heater refrigerant desuperheater.

In the specific embodiment disclosed a pump is used to circulate waterfrom the hot water tank through the heat exchanger and back to the hotwater tank when the compressor of the refrigeration circuit isenergized. A temperature sensing device is located to sense thetemperature of the incoming water. A second temperature sensing deviceis located to sense the temperature of the water being discharged fromthe heat exchanger. When both of these devices sense the propercondition a solenoid valve is opened such that the pump circulates waterthrough the heat exchanger and back to the hot water tank. Should eitherof these switches be closed the pump will continue to operate, however,water will then flow through a by-pass line located in parallel with theheat exchanger. This by-pass line has as a part thereof a flowrestriction which substantially reduces the volume flow of water throughthe by-pass line as compared to the flow through the heat exchanger whenthe valve is in the open position. The combination of the pump operatingcontinuously with the compressor and this flow restricted bypass lineacts to provide for continual sensing of the water temperature in thetank and additionally serves to reduce the overall energy input to thepump and the wear on the pump caused by continual cycling. In additionthereto by allowing for the limited flow through the by-pass line theheat energy generated by the pump, albeit a small value, may be suppliedto a relatively small flow of water.

Prior art devices disclose operating a pump continuously with acompressor, the use of a solenoid valve or other valve to control theflow of water through the heat exchanger and the use of a by-pass lineto circulate the flow of water around the heat exchanger. None of thesepatents disclose the combination of operating the pump simultaneouslywith benefits achieved by utilizing a restricted by-pass.

Additionally, the invention as claimed in this application comprises acoaxial fitting for supplying heated water from the heat exchanger tothe hot water tank. It has been found that the temperature of the waterflowing from the heat exchanger may exceed the normal dischargetemperature of water flowing from the hot water tank to the hot watersupply system. To prevent any unexpected high temperature water fromtraveling through the hot water system a coaxial fitting is utilized.This fitting discharges the water from the heat exchanger apredetermined depth into the top of the tank such that the water fromthe heat exchanger mixes partially with the water in the tank before itmay be discharged out the hot water outlet of the tank into the hotwater system.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a combination hotwater heater and refrigerant desuperheater accessory for installationwith a refrigeration circuit and a hot water system for transferringheat energy from the refrigeration circuit to the hot water system.

It is a further object of the present invention to provide a method oftransferring heat energy from a refrigeration circuit to a hot watersystem.

It is another object of the present invention to provide apparatus fordischarging heated water into a hot water system without allowing burstsof unexpectedly hot water to circulate through the hot water system.

These and other objects are achieved according to a preferred embodimentof the invention wherein there is disclosed a combination pump whichoperates simultaneously with the compressor of the refrigeration systemand a restricted flow by-pass line in parallel with the heat exchangersuch that in response to water temperature conditions the water iseither circulated primarily through the heat exchanger or circulatedaround the heat exchanger through the by-pass line. Additionally, acoaxial fitting is disclosed for discharging heated water from the heatexchanger into the hot water tank such that heated water mixes with thewater in the tank prior to being discharged out of the tank into the hotwater system.

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE is a schematic diagram of a vapor compression refrigerationsystem and a hot water system with the claimed apparatus such that heatenergy may be transferred between the two.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The embodiment described herein will be in conjunction with a vaporcompression refrigeration system and a residential-type hot water tank.It is to be understood that the invention applies likewise to varioustypes of refrigeration circuits wherein the refrigerant is superheatedand additionally to various size units such as residential, commercialand industrial. Additionally, although the hot water system as describedherein is appropriate for a residential application commercial and othersize hot water systems would be equally suitable.

Referring now to the FIGURE there can be seen a vapor compressionrefrigeration system having compressor 10 connected with discharge line50 to refrigerant conduit 11 of desuperheater 12. The refrigerantconduit 11 of the desuperheater is connected to condenser inlet line 52to condenser 14. Condenser 14 is connected to expansion means 16 whichis connected to evaporator 18 which is connected to the compressor tocomplete the closed vapor compression circuit.

A water system is disclosed having water inlet 60 supplying water to hotwater tank 22. Water inlet 60 extends through the top of the hot watertank and has a water inlet extension 61 extending towards the bottom ofthe tank such that cooler inlet water may be supplied to the bottom ofthe hot water tank. Feed line 64 is connected at a T-intersection towater inlet 60 such that water may be supplied topreheater-desuperheater package 100 (that part of diagram within thedashed lines) from either the water inlet or the hot water tankdepending upon whether or not water is being discharged from the tank.

Feed line 64 is connected to pump 30 which is connected to desuperheaterinlet line 66. Desuperheater inlet line 66 is connected to water conduit15 of desuperheater 12 which is connected to the desuperheater outletline 68. Desuperheater outlet line 68 is connected through solenoidvalve 36 to return line 70. In parallel with desuperheater 12desuperheater outlet line 68 and solenoid valve 36 is by-pass line 80having flow restriction 38. Flow restriction 38 may be a capillary tubeor fixed orifice device which creates a pressure drop. Return line 70 isconnected through joint 91 to return line extension 92 of coaxialfitting 90 such that hot water from the desuperheater may be conductedinto the reservoir of water within hot water tank 22. Hot water may bedischarged from hot water tank 22 through tank outlet 59 through theconduit portion 94 of coaxial fitting 90 into water outlet conduit 62 tosupply the hot water system.

Preheater-desuperheater package 100 includes pump 30 connected to powersource 24. Additionally, inlet thermal switch 32 and outlet thermalswitch 34 are connected in series with solenoid valve 36. Compressor 10of the refrigeration circuit is also connected to power source 24.Specifically, wire 26 is connected to compressor 10, to pump 30 and tosolenoid valve 36. Wire 28 is connected to compressor 10, pump 30 and tothermal switch 32. Wire 29 connects inlet thermal switch 32 to outletthermal switch 34. Wire 25 connects outlet thermal switch 34 to solenoidvalve 36.

Operation

When a demand is sensed such that the refrigeration circuit is operatedfor supplying heating or cooling compressor 10 is energized whichadditionally serves to energize pump 30 and to provide power to inletthermal switch 32. Once compressor 10 is energized hot refrigerant gasis discharged to desuperheater 12. This hot gas contains thermal energyincluding superheat energy, i.e. the energy rejected to cool the gas toits saturation temperature, the heat condensation (heat energy necessaryto condense the gas to a liquid). In the desuperheater only the heatenergy rejected by the gas being cooled to the saturated temperature isdesigned to be transferred to the water flowing therethrough. Incondenser 14 the heat of condensation of the refrigerant is rejected toa heat transfer media in heat transfer relation therewith.

When pump 30 is energized water is circulated from either water inlet 60or hot water tank 22 through the water inlet extension 61. If the hotwater system is removing water from water outlet 62 then water fromwater inlet 60 may flow directly to pump 30. If no outlet water is beingdischarged from the hot water tank then pump 30 will act to circulatewater drawn from the bottom of hot water tank 22 through water inletextension 61 and feed line 64. Pump 30 will circulate water through thewater conduit portion of desuperheater 12 when the inlet thermal switch32 and outlet thermal switch 34 are both closed energizing solenoidvalve 36. Inlet thermal switch 32 is a thermal sensing device set toopen if the incoming water temperature exceeds a predetermined valuesuch as 120° F. Outlet thermal switch 34 is a thermal sensing device setto open if the temperature of the water being discharged from the heatexchanger drops below a second predetermined value such as 140° F. Thiscombination of thermal switches acts to prevent flow through the heatexchanger if the water in the hot water tank is already sufficientlyheated i.e. the inlet water temperature is above 120° F. It also servesto prevent water flow through the heat exchanger if the water within theheat exchanger has not been sufficiently heated such that cold waterwould be returned to the tank. Consequently, once this temperature isover 140° F. the thermal switch closes such that that batch of waterwithin the desuperheater may be circulated back to the hot water tank.

By-pass line 80 connecting superheater inlet line 66 and return line 70has either formed as a part thereof or by its configuration a flowrestriction. This flow restriction serves to limit the volume flow ofwater through the by-pass line regardless of whether solenoid line 36 isin the open position or the closed position. If solenoid valve 36 isopen the pump experiences little head and pumps a preselected volume ofwater primarily through the heat exchanger. A small percentage of thiswater will flow through the by-pass and flow restriction such that notall of the water flows through the heat exchanger. However, shouldsolenoid valve 36 be closed preventing flow through the heat exchangerthen the only remaining flow path is through the restriction in by-passline 80. Since this restriction may be an orifice or other smalldiameter opening the pump 30 does not generate sufficient head to pump alarge flow of water therethrough. Consequently, a substantially reducedvolume flow from the volume that flows through the heat exchanger whenthe valve is opened flows through by-pass line 80 when the solenoidvalve is closed. This reduced flow when the valve is closed serves toallow inlet thermal switch 32 to constantly monitor the temperature ofthe water in the hot water tank. Should the solenoid valve 36 be closedbecause the temperature of the water in the water tank is sufficientlyhigh, then after either usage of tank hot water or heat loss from thetank additional heat energy is required. By constantly operating thepump inlet thermal switch 32 is able to sense when either of theseconditions is reached. Additionally, the energy generated by theconstant operation of the pump is transferred to the water flowingthrough the pump such that the small volume of water being circulated issomewhat heated as it is returned to the hot water tank.

The water being returned through return line 70 to the hot water tankpasses through coaxial fitting 90. Coaxial fitting 90 is designed to besecured to tank outlet 59 at the top of hot water tank 22 and to wateroutlet conduit 62 supplying the remainder of the hot water system.Coaxial fitting 90 has opening 93 formed in the side wall thereofthrough which return line extension 92 projects. Return line 70 isconnected to return line extension 92 by joint 91. The return lineextension is bent within the coaxial fitting and extends coaxial to theconduit portion 94 of the fitting into the reservoir of water containedin the tank.

Without a return line extension or its equivalent the heated water fromthe heat exchanger would be conducted directly into water outlet conduit62 and into the hot water system of the home. This water may be at atemperature hotter than anticipated and might provide an unexpectedblast of overheated water. To avoid this problem of unexpected warmerwater return line extension 92 is utilized such that the heated waterfrom the heat exchanger is discharged into the tank some distance belowthe top of the tank. The length of the return line extension extendinginto the tank is sufficient such that there is some mixing of the waterfrom the heat exchanger with the reservoir of water in the hot watertank prior to the hot water being conducted out of the tank. If the hotwater from the heat exchanger were simply dumped into the top of thetank that hot water might remain there since the tank is stratified.Again an unexpectedly warm spurt of hot water might be conducted out thehot water system upon demand therefor. The extension of the return lineserves to have the water from the heat exchanger injected into thereservoir a distance from the tank outlet enabling the water from thedesuperheater to be sufficiently mixed with the water in the reservoirsuch that the water being discharged out of the tank outlet will nothave an unexpectedly high temperature.

While the invention has been described with reference to a particularembodiment it is to be understood by those skilled in the art thatmodifications and variations can be effected within the spirit and scopeof the invention. It is further to be understood that although thepreferred embodiment is described as a residential system, principlesherein are likewise applicable to commercial and otherwise larger orsmaller refrigerations as well as larger or smaller hot water systems.

We claim:
 1. Apparatus for preheating hot water for a hot water systemusing heat energy from a refrigeration circuit including a refrigerantto water heat exchanger, the hot water system including a tank adaptedto contain a reservoir of stratified water such that warmer water is atthe top of the tank and colder water is at the bottom of the tank, atank outlet located in the top of the tank through which heated water iswithdrawn and inlet means located in the top of the tank adapted toprovide water to the tank which comprises:a fitting adapted to beconnected to the tank outlet in the top of the tank, the fittingincluding; a conduit portion through which heated water from the tankmay flow; a return line connected to the water outlet for supplyingheated water from the heat exchanger to the tank, and a return lineextension connected to the return line and extending through the top ofthe tank into the reservoir of water in the tank such that water fromthe heat exchanger is discharged into the reservoir a sufficientdistance from the conduit portion to allow for mixing of the water fromthe heat exchanger with the water in the reservoir prior to the waterfrom the heat exchanger being withdrawn from the tank outlet.
 2. Theapparatus as set forth in claim 1 wherein the return line has an ingressportion extending through a wall of the conduit portion of the fitting,a discharge portion extending into the reservoir in the tank and anelbow portion connecting the ingress portion to the discharge portion.3. A fitting adapted to connect a heated water outlet of a tankcontaining a reservoir of water to a heated water system and fordischarging water heated outside the tank into the tank whichcomprises:a conduit portion connecting the heated water outlet to theheated water system, a return line extension extending through theheated water outlet of the tank into the reservoir of water in the tank,the length that the return line extension extends into the tank beingsufficient such that the water heated ouside the tank and flowingthrough the return line extension at least partially mixes with thewater in the tank prior to being discharged from the tank through theheated water outlet; and wherein the conduit portion has an openingtherethrough and wherein the return line extension is secured within theopening through the conduit portion, said extension having one endexternal of the conduit portion for connection with the supply of waterheated outside the tank, and having the other end extend through theheated water outlet into the reservoir of water within the tank.
 4. Theapparatus as set forth in claim 3 wherein the return line extensioncomprises an ingress portion extending through the opening in theconduit portion, a discharge portion extending into the reservoir ofwater and an elbow portion connecting the ingress portion to thedischarge portion.
 5. A method of transferring heat energy from arefrigeration circuit used to heat or cool a space upon demand to a hotwater system which comprises the steps of:energizing the refrigerationcircuit on demand to circulate the refrigerant flowing within thecircuit through a heat exchanger; energizing a pump simultaneously withthe refrigeration circuit to circulate water between the hot watersystem and the heat exchanger; sensing the temperature of the water fromthe hot water system; sensing the temperature of the water beingdischarged from the heat exchanger; routing water primarily through theheat exchanger when the water from the hot water system is below a firstpredetermined temperature and the water being discharged from the heatexchanger is above a second predetermined temperature, and by-passing arestricted flow of water around the heat exchanger when either thetemperature of the incoming water is above the first predeterminedtemperature or the temperature of the water being discharged from theheat exchanger is below the second predetermined temperature, said stepof by-passing serving to allow continuous but reduced flow circulationof water between the tank and the heat exchanger to allow the watertemperature of the tank to be continuously monitored, and mixing heatedwater from the heat exchanger with water in the tank prior todischarging the heated water from the heat exchanger out the heatedwater outlet.
 6. A method of supplying heated water to a hot watersystem having a tank with a heated water outlet in the top of the tanksuch that the heated water may be reduced in temperature prior to beingcirculated through the hot water system which comprises the stepsof:maintaining a reservoir of water in the tank, said reservoir beingstratified with the colder water at the bottom and the hotter water atthe top; supplying water to the hot water system from the heated wateroutlet in the top of the tank, and introducing heated water to the tankthrough the heated water outlet, said heated water being conducted intothe reservoir of water in the tank such that the heated water mixes withthe water in the tank prior to being discharged from the heated wateroutlet of the tank.
 7. The method as set forth in claim 6 wherein thestep of supplying includes connecting the heated water outlet of thetank to the remainder of the hot water system with a conduit, andwherein the step of introducing includes mounting a return lineextension through the conduit extending through the heated water outletinto the reservoir of water such that the entering heated water is notdischarged at the same location as the water supplied to the hot watersystem is removed from the tank.